Hi Philip,
Sorry to be a bit late in my reply. Jed has explained the gist of what's
involved with using the Kokkos/Kokkos-kernels back-end for the PETSc
solves, though, depending on exactly how Xolotl creates its vectors,
there may be a bit of work required to ensure that the command-line
options specifying the matrix and GPU types get applied to the right
objects, and that non-GPU types are not being hardcoded somewhere (by a
call like "DMSetMatType(dm,MATAIJ)").
In addition to looking at the -log_view output, since Xolotl uses TS you
can specify "-ts_view" and look at the output that describes the solver
hierarchy that Xolotl sets up. If matrix types are being set correctly,
you'll see things like
Mat Object: 1 MPI processes
type: seqaijkokkos
(I note that I've also sent a related message about getting Xolotl
working with Kokkos back-ends on Summit to you, Sophie, and Phil in
reply to old thread about this.)
Were you also asking about how to use Kokkos for PETSc matrix assembly,
or is that a question for later?
Cheers,
Richard
On 2/15/22 09:07, Satish Balay via petsc-users wrote:
Also - perhaps the following info might be useful
Satish
----
balay@sb /home/balay/petsc (main=)
$ git grep -l download-kokkos-kernels config/examples
config/examples/arch-ci-freebsd-cxx-cmplx-pkgs-dbg.py
config/examples/arch-ci-linux-cuda-double.py
config/examples/arch-ci-linux-gcc-ifc-cmplx.py
config/examples/arch-ci-linux-hip-double.py
config/examples/arch-ci-linux-pkgs-dbg-ftn-interfaces.py
config/examples/arch-ci-linux-pkgs-valgrind.py
config/examples/arch-ci-osx-cxx-pkgs-opt.py
config/examples/arch-nvhpc.py
config/examples/arch-olcf-crusher.py
config/examples/arch-olcf-spock.py
balay@sb /home/balay/petsc (main=)
$ git grep -l "requires:.*kokkos_kernels"
src/ksp/ksp/tests/ex3.c
src/ksp/ksp/tests/ex43.c
src/ksp/ksp/tests/ex60.c
src/ksp/ksp/tutorials/ex7.c
src/mat/tests/ex123.c
src/mat/tests/ex132.c
src/mat/tests/ex2.c
src/mat/tests/ex250.c
src/mat/tests/ex251.c
src/mat/tests/ex252.c
src/mat/tests/ex254.c
src/mat/tests/ex5.c
src/mat/tests/ex62.c
src/mat/tutorials/ex5k.kokkos.cxx
src/snes/tests/ex13.c
src/snes/tutorials/ex13.c
src/snes/tutorials/ex3k.kokkos.cxx
src/snes/tutorials/ex56.c
src/ts/utils/dmplexlandau/tutorials/ex1.c
src/ts/utils/dmplexlandau/tutorials/ex1f90.F90
src/ts/utils/dmplexlandau/tutorials/ex2.c
src/vec/vec/tests/ex21.c
src/vec/vec/tests/ex22.c
src/vec/vec/tests/ex23.c
src/vec/vec/tests/ex28.c
src/vec/vec/tests/ex34.c
src/vec/vec/tests/ex37.c
src/vec/vec/tests/ex38.c
src/vec/vec/tests/ex4.c
src/vec/vec/tests/ex43.c
src/vec/vec/tests/ex60.c
src/vec/vec/tutorials/ex1.c
balay@sb /home/balay/petsc (main=)
$
On Tue, 15 Feb 2022, Satish Balay via petsc-users wrote:
Also - best to use petsc repo - 'main' branch.
And for install on crusher - check config/examples/arch-olcf-crusher.py
Satish
On Tue, 15 Feb 2022, Jed Brown wrote:
We need to make these docs more explicit, but the short answer is configure with
--download-kokkos --download-kokkos-kernels and run almost any example with
-dm_mat_type aijkokkos -dm_vec_type kokkos. If you run with -log_view, you should
see that all the flops take place on the device and there are few host->device
transfers. Message packing is done on the device and it'll use GPU-aware MPI.
There are a few examples of residual evaluation and matrix assembly on the device
using Kokkos. You can also see libCEED examples for assembly on the device into
Kokkos matrices and vectors without touching host memory.
"Fackler, Philip via petsc-users"<petsc-users@mcs.anl.gov> writes:
We're intending to transitioning the Xolotl interfaces with PETSc.
I am hoping someone (can) point us to some documentation (and examples) for
using PETSc's Kokkos-based interface. If this does not yet exist, then perhaps
some slides (like the ones Richard Mills showed at the NE-SciDAC all-hands
meeting) showing some examples could get us started.
Thanks for any help that can be provided,
Philip Fackler
Research Software Engineer, Application Engineering Group
Advanced Computing Systems Research Section
Computer Science and Mathematics Division
Oak Ridge National Laboratory